Morphing in ANSA
AIM
Understand what are the applications of the morphing phenomena in core automotive industries and also learn how to do the basic morphing in the preprocessor ANSA
OBJECTIVE
The morphing is a technique used in the indusrties for making the design optimisation faster.This is done in the FEA department itself .The model can be morphed according to the requirement so that the simulation results satisfy our requirement,.this is what basically happens in industries.And since it is a vast field we need to learn the basic understanding of the morphing technique .And the morphing is done by morphing team and the cAe engineers should have the basic understanding of the technique.So here we are learning the basic of the morphing tecnique and how we can do the morphing in ANSA.
MORPHING
Morphing is a technique in which we are altering the shape of the component based on our requirement.This usually happpens when in case of automobile industry is when the company is in need of hatchback car and they have a sedan model already exists .So in such a case we can use the morphing on the sedan to made it look like the hatchback and we can do the analysis to find out the results like NVH,Crash analaysis etc...So what basicallly here we are saving is the CAD modeling time.BEcause we otherwise need to made the cAD model for then hatchback at first and then we need to made the meshing on the Model and then we will be analysing it.So this usually takes time.So The FEA engineers itself made the morph of the model based on the requirement and do the reanalysis and if the anlyssis results are sufficient and then we can actually extract the cad model of the morphed mesh and we can hand it to the design team.So basically we can give the proper instructions to the design team.So this avoid the design instruction of the model and this simply saves a lot of time and saves a lot of devolopment cost.This sedan to hatchback morphing happens vice versa too and the morphing happens to several other applications as well.CAE approaches that allow to implement design modifications directly into the simulation models. Such a proactive role implies that new designs are explored directly on CAE models, thus avoiding the dependency on updated CAD models and avoiding the time consuming simulation-preparation activities (remeshing based on variant CAD).
This is very useful in expecially NVH analyis because of three main reasons.
1) Most of the companies had done the NVH analysis at the end of all other analysis ,By that time the CAD model will be already mostly fixed and other countermeasures adding based on the NVH analysis will be costly.So such an affair is difficult then.
2) The most of the time in NVH anlyis is spend for the assembling of the model basically integration of the model,So the time for the analysis for the engineers will be so small.So with the help of morphing already integrated thing doesn't require integration and so that the engineers get valuable time for analysis.
3)This is nothing but the fast implentation as we will be getting the analysis results easily and so that we can give enough ideas for the design changes to the design team.
If after the morphing we can see the qulaity of elements may not be there.So we can do a reconstruction or manual remesh on the areas where the results are very mandatory for us or the areas which are critical .
From the analysis ,in case a functional performance problem is identified, the morphing process allows a fast re-evaluation of different design alternatives so that countermeasures can already be incorporated in the first generation of CAD models. These initial models will thus have a better quality, so that the expected number of design iterations will be reduced.
In morphing we are creating a morphing Box in the model and we will be creating a morphing central nodes in it and the edges represent the shape functions and with the user control the shape changes .Morphing boxes are a hexahedral volume which contains special entities like the elements,Lines, volume elements,connection elements etc..These elements are called nested elements.By changing the shape of this box, the included elements will change their shape and position accordingly. Control points reside at morphing box corners and on the edges of morphing boxes and support free or controlled movements in the 3D space. The morphing box edges are splines, so they conserve their tangency continuity. Tangency is a constraint that can be defined between two successive morphing box edge.We can make enough splits in the Morphing boxes ,so that minute and small morphing can be done so as to match our requirement.That is the reason why this makes the devolopment phase faster.
Examples of Major applications in Automotive industry
1) Converting for eg: the sedan model into a hatchback model,we can use the morphing technique.So that within short span of time we can get the analysis results and also we will be getting the devolopmenet time shortened.
2) Automotive design styling applications use morphing since in NVH the sound pressure near the drivers ear needed to be find out.So in such a case these models are first subjected to three design changes that influence the car styling, the roof curvature, the windshield angle and the wheel base.
Fig 1 The controls blocks created on the roof and using the contriol block we make the dsign styling modifications in roof based on our requirement
3)Obtimization of subframe assemblies like front cradle which are attached to the Body in White can be done using the morphing easily.
Since the target for morphing is the outer surface, the inside structure of the vehicle will be morphed in proportion to the changes in outer geometry. As a result, internal components (e.g. seats, steering system) may be deformed incorrectly. This can partly be prevented by an appropriate choice of control blocks used while making morphing box . However, some components need to be restored to unmorphed condition. In case these components are attached to a morphed part of the body, some mesh modifications are required locally to restore the connectivity.During morphing it is important to reduce cross-section deformation as much as possible. In strongly morphed areas, the cross sections may be incorrectly squeezed together or stretched. Incorrectly morphed cross sections will strongly affect the global modes, body rigidity and crash analysis results
Fig 2 B-pillar before and after morphing (Top Cross Sectional view )
Procdure of Doing Morphing in ANSA
For doing the free box morphing , we need to construct a morphing box at the nodes where we need to make the morphing to be done.For that we need to go to Morphing Module > NEw >select Ortho > Place the radio button on entities > select the surface where we need to carry out the morphing > Middle mouse click . This will create a morphing box at that location. We can make the splits in the morphing box by Split > choose the edge where we need to make split > middle mouse click .
Fig 3 Morphing Box with splits
Then we can do morphing by moving the control points in the morphing box.This can be done by Box Morphing > Move > select the nodes we need to move for morphing > right click anywhere in Morphing box to create the local coordinate system > Move the nodes to desired location > Middle click .This will accept the morphing move.
Fig 4 before morphing
Fig 5 After Morphing
Fig 6 After all morphing processes ( with morphing Boxes )
Fig 7 Final component after morphing (after the deletion of the morphing boxes)
RESULTS
Fig 8 Component After Morphing Fig 9 Orginal component before morphing
Learning Outcome
The process of basic morphing in ANSA is learned and gets some descent idea about the industrial use of morphing technique.
Link for the files
https://drive.google.com/file/d/1haMxCKR1dI-JJpZ1LdugEaQP_YPt9DJp/view?usp=sharing